Evaporator



May 23, 1950 l J. E. PoTTHARs-r, JR

EVAPORATOR I5 Sheets-Sheet 1 Filed Ju`ne 11, 1945 FIG. I.

Las

INV EN TOR.

FIG. 2.

JOHN E. POTTHARST JR.

vMay Z3, 1950 J. E. POTTHARST, JR

EvAPoRAT'oR 3 Sheets-Sheet 2 Filed June 11, 1945 FIG. 5.

vNVENTOR. JOHN E.. PTTHARST JR@ May 23, A19.50 J. E. PoTTHARs-T, JR 2,509,108

EvAPoRAToR Filed June ll, 1945, 3 Sheets-Sheet 5 FIG. 6.

FIG. a.y

FIG. 9.

1N VEN TOR.

JOHN E. PoTTHARsT JR.

Patented May 23, 1950 UNITED STATES yPATENT OFFICE 3 Claims.

My invention relates to evaporators for use in distilling apparatus, and it comprises new and useful improvements in the same.

One of the objects of my invention is the provision of a new and improved evaporator which is adapted for assemblage with the other elements of a distilling apparatus into a compact unit requiring relatively little space. The structure and shape of the evaporators now in general use are not adapted for such purposes.

My improved evaporator is of such shape that the other elements of a distillation unit may be assembled therewith to complete a unit of such compactness as to be readily portable and to require but little space for its reception without sacricing efticiency or output capacity.

Another object in view is the provision of an evaporator wherein the entrainment of droplets of the solution or raw liquid in the vapor produced therefrom is prevented, and thus pure water or other condensate is produced by the distillating unit of which the evaporator is an element.

Other objects in view, and other improvements in structure and in arrangement of parts will appear from the following description.

In the accompanying drawings, wherein is illustrated a practical embodiment of the principles of my present invention:

Fig, l is a top plan view of the evaporator, the top of the vapor chamber being partially broken away to show parts and the bale being shown in section along the dotted line I-I in Fig. 2.

Fig. 2 is in part a view in front elevation, and in part in section taken along the dotted line 2-2 in Fig. l.

Fig. 3 is a plan View of the solution chamber which forms the bottom closure of the evaporator, the chamber being shown disassembled from the evaporator for the sake of olearness.

Fig. 4 is a transverse vertical section of the evaporator taken along the dotted line 4-4 in Fig. 2 and looking toward the right in the latter view.

Fig. 5 is a partial perspective of the evaporator sectioned along the dotted line 4 4 in Fig. 2 and looking toward the left of said line in the latter v1ew.

Fig. 6 is a plan view of the upper tube sheet.

Fig. 7 is a view in horizontal section taken along the dotted line I-'I in Fig. 4.

Fig. 8 is a view in horizontal section taken along the dotted line 8-8 in Fig. 4.

Fig. 9 is a plan View of the lower tube sheet.

Referring to the drawings, I0 indicates the III vapor chamber which forms the upper portion of the evaporator and is dened by the top closure II and the inclosing skirt wall I2 which is supported on and is welded or otherwise attached to the upper tube sheet I3.

The chamber I0, as shown in Fig. 1, is oblong, having straight parallel front and rear walls, and semi-circular end walls.

At the rear center of the chamber the wall I2 is provided with a port I4 which is arranged for connection to a conduit for the withdrawal of vapors from the chamber.

The central portion of the tube sheet I3 is provided with an opening I5, of substantially hour-glass shape disposed transversely of the tube sheet, having arcuate side walls concentric with the semi-circular ends of the tube sheet, and straight end walls. Within the circles dened by the semi-circular ends of the tube sheet I3 and the arcuate side walls of the opening I5 the tube sheet is provided with two circular groups of tube holes I6, the individual holes of a group being closely adjacent to each other.

I1 indicates the lower tube sheet having cylindraceous end portions in which are provided groups of tube holes I6 corresponding in number and arrangement to the like tube holes in the upper tube sheet I3.

I8 indicates the banks of vertical tubes which extend between the tube sheets and have their opposite ends rolled or welded in the holes I6 to provide tight joints.

The central portion of the lower tube sheet I'I is in the form of a relatively narrow neck I9 in the center of which is provided an opening 20 of substantially smaller dimensions than those of the opening I5 in the upper tube sheet. The side walls of the opening 20 are curved concentrically with the ends of the tube sheet.

Surrounding the two banks of tubes and extending between the upper and lower tube sheets are the two tubular shells 2I whose upper and lower ends are attached by tight joints, as by welding, to the tube sheets, each shell enclosing one of the two banks of tubes and forming a heating chamber for the tubes.

The lower end of the evaporator is closed by the solution chamber 22 which has a closed bottom and an upwardly extending vertical wall or skirt 23 which is flanged outwardly at the top to iit against and to be secured as by bolts to the under side of the lower tube sheet I'I.

The perimetral contour of the chamber corresponds to that of the lower tube sheet.

24 indicates the front wall of the downtake,

the upper end of which is welded or otherwise attached to the underside of the upper tube sheet I3. The lower end of the wall 24 extends into and is welded to the side of the opening 2U. The vertical edges 25 of the wall 24 are welded to the shells 2l. The upper portion of the wall 24 is vertical but adjacent its lower portion it inclines inwardly as shown at 2&5, and the lower extremity 2l is Vertical and extends into and is welded to the wall of the opening 2t in the lower tube sheet.

28 indicates the rear wall of the downtalre which is also welded along its vertical edges to the shells 2i and at its upper end to the underside of the tube sheet i3 and at its lower end to the wall of the opening 2t .in the tube sheet il.

The upper portion of the wall 28 is vertical, its intermediate portion is inset, and the wall then is inclined downwardly and inwardly, merging into a vertical portion the lower end of which is welded to the edge of the opening 29.

Thus the upper end of the downtake, indicated generally by the numeral 29, is open through the opening i to the vapor chamber ii! while its reduced lower end is open to the solution chamber 22.

30 indicates a baffle which depends within and extends from side to side of the downtake, its vertical edges being Welded to the shells 2i.

The upper extremity of the baille S9 is attached to or integral with the inner or rear wall of the box 3 i, the closed top of which is spaced from the top closure il of the vapor chamber it to permit the circulation of vapor within the latter. The side walls oi the box 3i extend to and are welded to the wall i2 of the vapor chamber. 32 indicates a conduit having its inner end connected to a port in the inner wall of the-box 3i and its outer end to the port i4. The bottom of the box 3i is open for the entrance of vapor from the downtake traveling upwardly in front of the bale 3i?.

The upper portion of the baiiie Sii is vertical as shown, forming with the rear wall E of the downtake a vertical passage 3,3 for the downward travel of vapor from the vchamber lil. Below the vertical portion of the baiiie is a forwardly and downwardly inclined intermediate portion of the baie terminating in the vertically depending portion 34 which forms with the iront wall 2t a passage 35 through which the vapor travels upwardly into the box 3l and thence through the conduit 32 and out through the port i5.

36 indicates a feed pipe connected to a port in the front wall 2.4 of the downtake for the introduction of the solution to be vaporized. S1 indicates the blowdown or withdrawal pipe for concentrated solution, said pipe extending through the front wall 24 of the downtake and extending upwardly within the lower portion of the downtake to the proper elevation to maintain the desired volume oi solution in the blowdown and in the tubes i8. rihe level of solution in the downtake is below the lower end of thebaiiie.

38 indicates the condensate withdrawal pipe which connects to a manifold 39 extending between the shells 2i at the lower ends of the latter and connected to the space within the shelis around and between the tubes through ports eli in the shells.

4i indicates a manifold duct extending between the shells at the rear of the evaporator and adjacent the bottom of the shells. yThe extremities oi the manifold connect with Athe in- 4 terior of the shells through ports 42 in the walls of the shells.

The manifold is provided with a port 43 for the introduction of vapor or steam, or both, at a temperature higher than the boiling temperature of the solution to boil the latter in the tubes I6 and evolve vapors therefrom.

During the operation of the evaporator, the impure solution is continuously supplied to the chamber 22 through the feed pipe 35 and a body of the solution is maintained in the tubes i8 and the downtake 29 at the level determined by the upper inlet end of the blowdown pipe 3l' and below the lower end of the bafe 3Q. The vapors generated from the solution in the tubes rise into the chamber i0 and travel downward through the passage 3 3 in back of the baie 3o and then reverse their direction and pass up through the passage 35 and out the box 3| and thence to the port I4.

It is a well known fact that to successfully separate the droplets of entrained liquid from a current of steam, itis usually necessary to reverse the direction of the current to reverse the direction of the iiow at high velocity so that the momentum of the droplets will retard the reversal of their direction of travel with the steam, thus permitting their projection against a collooting surface.

In the case of my improved evaporator, the initial travel of the vapors in which the droplets are entrained from the vapor chamber iii is downward through passage 33 between the baiiie iii and the rear wall 28 of the downtalre, the current oi vapors then abruptly reversing its path of travel around the lower extremity or" the barile into -a 'vertically upward direction through the passage 35, the box 3i, the conduit 32 and out through the port i4.

This abrupt reversal of direction of the travel of the vapors causes the droplets to be projected downwardly onto the surface of the solution in the lower end of the downtake. The condensate formed in the lower portions of the shells from the steam and hot vapor introduced through t Ae port 43 is withdrawn by the condensate line 33.

The supply of solution to the chamber 22 is greater than that required to compensate for the evaporation of solution in the tubes, and therefore an overflow into the upper end of the blowdown 3l is continuous. Thus the concentrated solution is continuously withdrawn :from and fresh solution supplied to the evaporator.

'lt is evident that the exterior contour of the evaporator especially recommends its employment in a distillation unit which must be cornpact so as to be conveniently portable and capable or" being iinstalled in a contracted space, such as in the yhull of a small naval vessel.

I t is further evident that by the use of my improved evaporator a better and purer character of condensate may be produced as the droplets of solution are ymore efectually prevented from entrainment in the vapors as the latter pass from the evaporator to the compressor.

I claim:

l. A compact evaporator consisting of a pair of spaced vertically disposed cylindrical shells closed at their ends and each having a plurality of tubes passing therethrough, means deiining a common vapor chamber open to the tubes of each shell at the top'oi the latter, means dening a common solution chamber open to the tubes of ieach-shell atthe-bottorn of vthe latter, front and rear Vwalls connecting said shells to complete with said shells and chambers, a common downtake open to both of said chambers, said walls connecting said shells at substantially their great diameters at the top adjacent the vapor chamber and approaching each other adjacent the bottom forming a throat which opens to said solution chamber, an upwardly open blowdown pipe in the downtake above said throat, a downwardly open feed pipe in said throat below said blowdown pipe, a baiiie connecting said shells intermediate said front and rear walls, a vapor withdrawal pipe communicating with the upper end of the downtake and on one side of said bale, a common vapor supply duct connected to the interior of both of said shells, and a common pipe for withdrawing condensate from the interior of said shells.

2. A compact evaporator consisting of a pair of spaced vertically disposed cylindrical shells closed at their ends and each having a plurality of tubes passing therethrough, means defining a common vapor chamber open to the tubes of each shell at the top of the latter, means defining a common solution chamber open to the tubes of each shell at the bottom of the latter, front and rear Walls connecting said shells to complete with said shells and chambers a common downtake open to both of said chambers, said walls connecting said shells at substantially their great diameters at the top adjacent the vapor chamber and approaching each other adjacent the bottom forming a throat which opens to said solution chamber, an upwardly open blowdown pipe in the downtake above said throat, a downwardly open feed pipe in said throat below said blowdown pipe, a barile connecting said shells intermediate said front and rear walls, a vapor withdrawal pipe communicating with the upper end of the downtake and on one side of said bae, a common vapor supply duct of relatively large capacity connected to the interior of both of said shells for the supply of vapor to the interior of the latter, and a common pipe of less capacity for the withdrawal of condensate from said shells.

3. A compact evaporator consisting of a pair of spaced vertically disposed cylindrical shells closed at their ends and each having a plurality of tubes passing therethrough, means deiining a common vapor chamber open to the tubes of each shell at the top of the latter, means deiining a common solution chamber open to the tubes of each shell at the bottom of the latter, front and rear walls connecting said shells to complete with said shells and chambers a common downtake open to both of said chambers, said walls connecting said shells at substantially their great diameters at the top adjacent the vapor chamber and approaching each other adjacent the bottom forming a throat which opens to said solution chamber, an upwardly open blowdown pipe in the downtake above said throat, a downwardly open feed pipe in said throat below said blowdown pipe, a baiiie connecting said shells intermediate said front and rear walls, a vapor withdrawal pipe communicating with the upper end of the downtake and on one side of said baie, a third wall connecting said shells to complete with said shells and one of said first named walls a common manifold duct communicating at its opposite ends to the interior of the shells, a pipe for supplying vapor to said duct, and a fourth wall connecting said shells to complete with said shells and the other of said iirst named walls a common connection for the withdrawal of condensate from the interior of said shells below said duct and at a level adjacent the bottom oi. the latter.

JOI-IN E. POTTHARST, JR.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Date 894,407 Suzuki July 28, 1908 FOREIGN PATENTS Number Country Date 56,668 Norway June 15, 1936 270,644 Italy Jan. 16, 1930 

